Lock release systems



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1964 J. G. w. LEE I S 3,144,761

LOCK RELEASE SYSTEMS Filed Oct. 24, 1960 2 Sheets-Sheet 1 l4 l2 l0 4Inventor F/G. a d

By K7,- LJ cQocJis Attorney Aug. 18, 1964 J. G. w. LEE Y 3,144,761

LOCK RELEASE SYSTEMS Filed on. 24, 1960 2 Sheets-Shet 2 llwenlor y g mFC, S

Attorney United States Patent 3,144,761 LOCK RELEASE SYSTEMS John GwynWilliam Lee, Welwyn, England, assignor to The De Havilland AircraftCompany Limited Filed Oct. 24, 1960, Ser. No. 64,543 Claims priority,application Great Britain Nov. 4, 1959 18 Claims. (Cl. 70-277) Thisinvention relates to lock release systems.

In the past, lock releases of safes and strong rooms have been operatedmechanically by keys or combination dials. By the present invention, alock release is operable by radiations, particularly infra-redradiations, and is less susceptible to successful interference than lookreleases heretofore.

According to the invention, therefore, a lock actuating system comprisesa source of coded radiation pulses, a detector of radiation pulses and acomparator adapted to compare output signals of the detector with apreset sequence of signals and to operate the lock release uponcompletion of a correct sequence of radiation pulses.

The invention also includes, in a lock release system comprising a lockrelease operatively connected to a lock; a detector of radiation pulsesassociated with the lock, a comparator adapted to compare the outputsignals of the detector with a preset sequence of signals, and aportable source of coded radiation pulses arranged to be applied to saiddetector, said comparator being operatively connected to the lockrelease to operate the latter only upon completion of a correct sequenceof radiation pulses from said source.

A further object of the invention is, in a lock release systemcomprising a lock release operatively connected to a lock; a detector ofradiation pulses associated with the lock, a source of a preset sequenceof signals, a comparator to compare output signals of said detector withsignals from said source, a portable source of coded radiation pulsesarranged to be applied to said detector, said comparator beingoperatively connected to the lock release to operate the latter torelease said lock only upon coincidence of said output signals and saidsignals from said source.

Still further, the invention comprehends, in a lock release system, adetector of radiation pulses, a source of a preset sequence of signals,a comparator to compare output signals of said detector with signalsfrom said source, a reset device operable to prevent operation of saidlock release, a source of coded radiation pulses arranged to be appliedto said detector, said comparator being operatively connected to saidlock release and said reset device to operate said lock release uponcoincidence of said output signals and said signals from said source andto operate said reset device upon lack of such coincidence.

In the accompanying diagrammatic drawings:

FIGURE 1 is a section of a key or source of coded radiation pulses;

FIGURE 2 is a broken front view of part of the key of FIGURE 1;

FIGURE 3 is a diagram of part of a detector of radiation pulses;

FIGURE 4 is an electrical circuit diagram of the detector;

FIGURE 5 is a diagram of the detector and comparator; and

FIGURE 6 is a front view of part of the comparator.

The lock release system consists of a detector release device within thesafe and a key to operate the device. The key consists of a smallinfra-red source and chopper which sends out information in the form ofradiation pulses, the wave length and sequence of which is coded.

These are applied to the detector release device which compares themwith a standard coded set of pulses and if they are correct releases thelock.

The key 10 (FIGURE 1) comprises a battery operated lamp 12 which sendslight through a stop and shutter 14 to fall on the edge of a rotatablechopper disc 16. The edge of the chopper disc 16 (FIGURE 2) is dividedinto a series of forty stations. At alternate stations 17, 19, 21, 23,25, termed dwell stations, the material of the disc is cut away to apredetermined extent. Between the dwell stations, stations 18, 20, 22,24, 26 termed pulse stations at which the material of the disc is eithernot cut away (stations 24 and 26) or is cut away to an extent twice thatof the dwell station cut away (stations 18, 20 and 22).

Light falling on the chopper disc 16 at the dwell stations passesthrough a predetermined area. At the pulse stations, light either passesthrough twice this area or does not pass at all. Light from the discpasses through a filter 30 which allows to pass only radiations within apredetermined range of wave lengths, for example 2.2 '[0 2.711.

The chopper disc 16 is rotatable in steps by a manually operableescapement drive 32. Each step brings another dwell station in front ofthe stop and shutter 14, so that during the stop light passes through apulse station. The drive 32 is such as to ensure a maximum speed of thedisc through pulse stations and to ensure at least a minimum period oftime during transit of dwell stations.

The output of the key 10 is thus a steady amount of infra-red radiationinterrupted by pulses either of a greater amount of radiation or noradiation. The exact coded sequence of pulses may be obtained bypermanent removal of material from the disc or may be set by radiallyslidable shutters at the pulse stations.

In the wall of the safe is a disguised window 40 (FIG- URE 3) ofgermanium through which radiations from the key may fall on a detector42 (FIGURE 5). Behind the window 40 and at 45 thereto is an opticalfilter 44 (FIGURE 3) which allows to pass only radiations within thepredetermined range of wavelengths. These fall on a first radiationsensitive cell 46. Other radiations are reflected to a second radiationsensitive cell 48. The cells are lead sulphide cells and are connectedin series with a resistor 50 (FIGURE 4) between an H.T. source andearth. The cell 48 is shunted by a resistor 52 and a tapping 54 is takenfrom between the cells to an amplifier 56 (FIGURE 5).

The cell 48 is so padded that when white light falls on the filter 44,the output signal from between the cells is zero. A signal from thetapping 54 is obtained only when the detector is illuminated withradiations of the predetermined range of wavelengths. In this case, thecell 46 is energised, and the cell 48 functions etfectively as aresistive load. The level of signal will depend on the amount ofradiation received.

The amplifier 56 receives signals from the tapping 54 and differentiatesthese so as to provide an output of a negative signal pulse followed bya positive signal pulse when the incoming signal is zero, and a positivesignal pulse followed by a negative signal pulse when the incomingsignal is a maximum. The output pulses from the amplifier 56 are passedto a gating amplifier and sorter circuit 60 in which the second of eachpair of incoming pulses is is eliminated and the first of each pair ofincoming pulses is directed to one or other of two output channels 62and 64, in accordance with its sign, positive pulses to the channel 62and negative pulses, after reversal, to the channel 64. The channels 62and 64 lead to a distributor circuit 66. The signals in the channels 62and 64 are directed either to channels 70 and a mm 7 72 or to channels72 and 74 by the distributor circuit 66 in accordance with coded signalsreceived from an index pick-off 68. Channels 70 and 74 lead to anescapernent release circuit 76 which upon receipt of a pulse, operatesan escapernent 78 to permit a step rotation of a shaft 80. Channel 72leads to a reset release circuit 82, which upon receipt of a pulse,operates a reset device 84 which over-rides the escapernent 78 andreturns the shaft 80 to its initial position. The shaft 80 has an indexdisc 86 which has twenty code stations 88, 90, 92, 94, 96, at each ofwhich is a magnctised portion 98. The magnetised portion 98 at anyparticular code station may be close to the periphery (stations 94 and96) or spaced therefrom (stations 88, 90 and 92).

Each step of the shaft 80 brings another code station under the indexpick-off 68 from which signals are derived from the distributor circuit66, the signals being negative or positive in accordance with theposition of the magnctised portion 98. The output of the pick-off 68 isthus a coded sequence of electrical signal pulses which is predeterminedby the positions of the magnctised portions 98 on the disc 86 and agreeswith the coded sequency of radiation pulses from the key 10.

The speed of the escapernent 78 is such that the step movement of thedisc 86 from one code station to the next takes place in the period oftime during which the chopper disc 16 remains on one dwell station.

The step movement of the disc 16 from one dwell station through a pulsestation to the next dwell station takes place whilst the disc 86 remainson one code station. The shaft 80 carries a lock release 100 which aftersuccessful rotation of the shaft through twenty stations releases thesafe lock (not shown).

The reset device 84 which resets the shaft is clockdriven to over-rideand prevent operation of the escapement 78 during predetermined periodsof time, for example night and weekends.

In operation, the key 10 is presented to the germanium window 40 so thatlight from the filter 30 passes directly through the window. The batteryoperated lamp 12 is switched on 'and power from the electrical parts ofthe detector release device and for the drive to the shaft 80 is madeavailable by a contact switch. At this time the index disc 86 is in aposition in which the pick-off 68 lies over the code station 88 with themagnctised portion 98 spaced from the periphery, as shown in dottedlines in FIGURE 6. This results in a positive signal being applied tothe distributor circuit 66 which thus directs incoming signals from thechannels 62 and 64 to the channels 70 and 72.

The escapernent drive 32 is now manually operated so that the chopperdisc 16 moves from one dwell station 17 to the next dwell station 19.During such move, the disc passes through the pulse station 18 in whichlight from the stop and shutter 14 passes through a full size cutaway,as shown in dotted lines in FIGURE 2.

This light passes through the filters 30 and 44 to the cell 46 whichproduces an increased positive signal dur ing its exposure to theincreased amount of radiation. This signal is differentiated in theamplifier 56 into a positive pulse signal followed by a negative pulsesignal which pass to the gating amplifier and sorter circuit 60 wherethe negative pulse signal is eliminated and whence positive signal isdirected to the positive channel 62. It is then directed by thedistributor circuit 66 to the channel 70 and escapernent release circuit76 to operate the escapernent 78, thus permitting the shaft 80 to rotatethrough one step.

The time delay in the circuit is such that this step is taken only whenthe chopper disc 16 has reached the dwell station 19. In its newposition, the disc 86 is at the next code station 90 in which a positivesignal is derived by the pickoff for the distributor. This directssignals from the channels 62 and 64 to the channels 70 and 72 so that ifthe key 10 continues to be operated a radiation pulse due to the cutaway shape of the pulse station 20, causes a positive signal to pass andoperate the escapernent 78.

This is again repeated for the next stations of the discs 86 and 16.

In the code station 94, however, the pick-off 68 lies over a magnctisedportion 98 adjacent the periphery of the disc 86 and a negative signalis applied to the distributor circuit 66 so that the latter directsincoming signals in the channels 62 and 64 to the channels 72 and 74.

As the disc 16 passes from the dwell station 23 to the dwell station 25,the passage of light is blocked by the material of the pulse station 24.This results in a zero signal from the cell 46, so that a negative pulsesignal followed by a positive pulse signal is derived from the amplifier56 after removal of the positive signal and passed by the gatingamplifier and sorter circuit 60 to the channel 64 and by the distributorcircuit 66 to the channel 74 to energise the release circuit 76 tooperate the escapement 78.

Coded pulse signals continue to operate the escapernent 78 so long asthe radiation pulses coded by the disc 16 agree with the signals derivedfrom the pick-off 68 and coded by the disc 86. After twenty correctsignals have been received, the lock is released.

If at any time an incorrect radiation pulse is received, the resultantpulse signal is directed by the distributor circuit 66 to the channel 72so that the reset device 84 is operated by the circuit 82 and the lockis not released. An alarm may be initiated at the same time.

It will be understood that the wavelength of the radiation pulses usedneed not be that stated, but is preferably within the infra-red range asradiation sensitive cells for this range are available. For the sake ofsimplicity it is also desirable to keep the wavelength within thenear-visible range of wavelengths.

Instead of magnetised portions, the disc 86 may carry contacts forengagement by a pick-off, and from which signals of opposite polaritycould be obtained.

The comparator circuit in which signals from the detector are comparedwith signals from the driven disc 86 may differ from that described. Forexample the polarity of certain signals from the amplifier may bereversed in the distributor circuit 66 instead of in the sorter cirter.Alternatively the signals from the amplifier 56 may be directed unsortedto a distributor and thence to two sorter circuits.

The index disc pick-off is described as producing negative and positivesignals, but it will be understood that signals of the same polarity maybe produced in one of two different channels to control the distributor.Alternatively either one or two signals may be produced by the pick-offdepending upon the particular code station.

It will be appreciated that with forty stations, the chopper disc givesa code of twenty digits with over 1,000,000 combinations. If less ormore combinations are required, less or more stations are used.

Before presentation of the key to the window, the index disc may be in aposition of rest and upon such presentation be moved up to the correctposition for the first pulse. In this case the chopper disc may have ablank starting portion on its periphery between the first dwell stationand the last pulse station.

I claim:

1. A lock release actuating system comprising a substantially steadysource of radiation, an angularly movable chopper arranged to vary theamount of radiation passing from said source to produce a predeterminedsequence of radiation pulses, a detector of radiation pulses, and acomparator operable to compare output signals of the detector with apreset sequence of signals and to initiate a v lock-releasing operationupon completion of a correct seincluding an escapement by which thechopper is movable stepwise.

3. A lock release actuating system as claimed in claim 2, wherein thechopper has dwell portions which allow a predetermined amount ofradiation to pass, and pulse portions between said dwell portions, whichallow different amounts of radiation to pass in a predeterminedsequence.

4. A lock release actuating system as claimed in claim 3, wherein thechopper is in the form of a disc having dwell portions of one diameterand pulse portions of a diameter chosen from two diameters, one greaterthan and the other less than said dwell portion diameter.

5. A lock release actuating system as claimed in claim 4, wherein thepulse portions comprise shutters radially movable between positionscorresponding to said diameters.

6. A lock release actuating system as claimed in claim 2, wherein theescapement is manually rotatable.

7. A look release actuating system comprising a detector of radiationpulses, a comparator adapted to compare the output signals of thedetector with a preset sequence of signals, and a portable source of apredetermined sequence of radiation pulses arranged to be applied tosaid detector, said portable source including a substantially steadysource of radiation and an angularly movable chopper arranged to varythe amount of radiation passing from said steady source to produce saidsequence of radiation pulses, and said comparator being operativelyconnected to initiate a lock-releasing operation upon completion of acorrect sequence of radiation pulses from said portable source.

8. A system as claimed in claim 7, including an escapement by which thechopper is movable stepwise.

9. A system as claimed in claim 8, wherein the chopper has dwellportions which allow a predetermined amount of radiation to passs, andpulse portions between said dwell portions, which allow difierentamounts of radiation to pass in a predetermined sequence.

10. A system as claimed in claim 9, wherein the chopper is in the formof a disc having dwell portions of one diameter and pulse portions of adiameter chosen from two diameters, one greater than and the other lessthan said dwell position diameter.

11. A lock release actuating system comprising a detector of radiationpulses, a source of a preset sequence of signals, a comparator tocompare output signals of said detector with signals from said source,and a portable source of a predetermined sequence of radiation pulsesaranged to be applied to said detector, said portable source including asubstantially steady source of radiation and an angularly movablechopper arranged to vary the amount of radiation passing from saidsteady source to produce said sequence of radiation pulses, and saidcomparator being operatively connected to initiate a lock-releasingoperation only upon coincidence of said output signals and said signalsfrom said source of a preset sequence of signals.

12. A system as claimed in claim 11, including an escapement by whichthe chopper is movable stepwise.

13. A system as claimed in claim 12, wherein the chopper has dwellportions which allow a predetermined amount of radiation to pass, andpulse portions between said dwell portions, which allow difierentamounts of radiation to pass in a predetermined sequence.

14. A system as claim in claim 13, wherein the chopper is in the form ofa disc having dwell portions of one diameter and pulse portions of adiameter chosen from two diameters, one greater than and the other lessthan said dwell portion diameter.

15. In a lock release actuating system, a detector of radiation pulses,a source of a preset sequence of signals, a comparator to compare outputsignals of said detector with signals from said source, a reset deviceoperable to prevent any lock releasing operation, a source of codedradiation pulses arranged to be applied to said detector, saidcomparator being operatively connected to the reset device and connectedto initiate a lock releasing operation upon coincidence of said outputsignals and said signals from said source and to operate said resetdevice upon lack of such coincidence.

16. A system as claimed in claim 15, wherein the source of the presetsequence of signals includes an angularly movable member from which thesequence is derived, said comparator being arranged upon coincidence topass said output signals to drive said angularly movable member in onedirection and upon lack of coincidence to pass said output signals tosaid reset device to drive said angularly movable member in the otherdirection, said angularly movable member being operatively connected toinitiate a lock releasing operation upon completion of angular movementon said one direction.

17. A system as claimed in claim 16, wherein the angularly movablemember is movable stepwise.

18. A system as claimed in claim 17, including an escapement to drivethe angularly movable member in said one direction arranged to bereleased by the receipt of output signals from the comparator.

References Cited in the file of this patent UNITED STATES PATENTS1,923,968 Chase Aug. 22, 1933 2,008,150 Nelson July 16, 1935 2,499,889Teichmann Mar. 7, 1950 2,677,814 Miller May 4, 1954 2,779,874 SonborghJan. 29, 1957 2,909,711 Neville et a1 Oct. 20, 1959 2,936,607 NielsenMay 17, 1960

1. A LOCK RELEASE ACTUATING SYSTEM COMPRISING A SUBSTANTIALLY STEADYSOURCE OF RADIATION, AN ANGULARLY MOVABLE CHOPPER ARRANGED TO VARY THEAMOUNT OF RADIATION PASSING FROM SAID SOURCE TO PRODUCE A PREDETERMINEDSEQUENCE OF RADIATION PULSES, A DETECTOR OF RADIATION PULSES, AND ACOMPARATOR OPERABLE TO COMPARE OUTPUT SIGNALS OF THE DETECTOR WITH APRESET SEQUENCE OF SIGNALS AND TO INITIATE A LOCK-RELEASING OPERATIONUPON COMPLETION OF A CORRECT SEQUENCE OF RADIATION PULSES.